A female "vampire" unearthed in a mass grave near Venice, Italy, may have been accused of wearing another evil hat: a witch's.

The 16th-century woman was discovered among medieval plague victims in 2006. Her jaw had been forced open by a brick—an exorcism technique used on suspected vampires in Europe at the time.

The discovery marked the first time archaeological remains had been interpreted as those of an alleged vampire, project leader Matteo Borrini, a forensic archaeologist at the University of Florence in Italy, said when the skull was first revealed in March 2009.

New investigations have now shed light on who this "vampire" was, why people may have suspected her of dabbling in the dark arts, and even what she looked like.

"There is a piece of history to rewrite, to see this individual again after 500 years and also try to understand why the myth of vampire started," Borrini says in a new National Geographic Channel documentary. (The National Geographic Channel is part-owned by the National Geographic Society, which owns National Geographic News.)

Belief in vampires was rampant in the Middle Ages, mostly because the process of decomposition was not well understood, Borrini says.

For instance, as the human stomach decays, it releases a dark "purge fluid." This bloodlike liquid can flow freely from a corpse's nose and mouth.

Since tombs and mass burials were often reopened during plagues to add new bodies, Italian gravediggers saw these decomposing remains and may have confused purge fluid with traces of vampire victims' blood.

In addition, the fluid sometimes moistened the burial shroud near the corpse's mouth so that the cloth sagged into the jaw. This could create tears in the cloth that made it seem as if the corpse had been chewing on its shroud.

Vampires were thought by some to be the causes of plagues, and the superstition took root that shroud-chewing was the "magical way" that vampires infected people, Borrini said.

Inserting objects—such as bricks and stones—into the mouths of alleged vampires was thought to halt the spread of disease.

To flesh out more details about the Venice vampire, Borrini assembled a team of scientists.

Paleonutritionists pulverized some of the woman's remains—discovered along with the skull—to look for certain elements in food that settle in the bones and endure after death.

The team found that the woman had eaten mostly vegetables and grains, suggesting a lower-class diet.

DNA analysis revealed that the woman was European, and a forensic odontologist ascertained the woman's age by examining the skull's long canine teeth with an advanced digital x-ray device.

The results showed that the woman was between 61 and 71 years old when she died. Borrini was "quite shocked" by this finding—most women didn't reach such advanced ages in the 16th century, he says in the documentary.

In medieval Europe, when fear of witches was widespread, many people believed the devil gave witches magical powers, including the ability to cheat death.

That means such a relatively old woman—suspected after death of being a vampire—may have been accused in life of being a witch, the researchers say.

Witches Were Child-Eaters?

But old age alone probably wouldn't spur an accusation of witchcraft, said Jason Coy, an expert in European witchcraft and superstition at the College of Charleston in South Carolina, who was not part of the new study.

Though average life expectancy in 16th-century Europe was low, around 40, that doesn't mean most people died at 40, he said via email. It means infant mortality was high, bringing down the average. If people lived past childhood, they stood a good chance of living into their 60s.

So the Venice vampire was old, but not "freakishly so," Coy said.

Rather, Europe's misogynistic society specifically linked old women with witchcraft, because people "assumed that old women—especially widows—were poor, lonely, weak, and unhappy, and thus could be lured by the devil's promises of wealth, sex, and power into forming a pact with him," Coy said.

At the height of the European witch-hunts, between A.D. 1550 and 1650, more than 100,000 people were tried as witches and 60,000 were executed—the vast majority of them old women.

Germany was the witch-hunt heartland, Coy said. Italy was relatively "mild" in its treatment of witches, although the country was also rife with superstitions and protective charms. (Related: "Halloween Shines Light on Witchcraft Today.")

In many historical references of the time, witches were said to eat children—possibly the origin of the Hansel and Gretel story, he added.

"So you could say that there is a tenuous link between flesh-eating zombies like your 'Venetian vampire' and witches: They were both feared for breaking the ultimate taboo—eating human flesh."

"Vampire of Venice" an Ordinary Woman

For the last step in forensic archaeologist Borrini's work, he called on 3-D imaging experts to produce a digital model of the skull.

He then put markers where muscle attachments would have existed to reconstruct and rebuild the Venice vampire's face. The result was the face of an "ordinary woman," which perhaps brings the accused some "historical justice" centuries after her death, he said.

"It's very strange to [leave] her now," he lamented, "because after this year it's sort of a friendship that's created between me and her."